In accordance with the development of hardware technology, user environment and the like, various and complex functions are integrally implemented in a portable terminal such as a smart phone in addition to basic functions for communication.
A typical example is a camera module in which various functions such as autofocus (AF), optical image stabilization (OIS) are implemented. In recent years, voice recognition, fingerprint recognition, iris recognition or the like is also mounted to a mobile terminal for certification or security.
A camera module or device mounted to a portable terminal or the like includes a diaphragm for controlling the amount of light introduced into a lens. The diaphragm may have various structures according to embodiments, but generally one or more blades (IRIS) having a wing shape are provided to open or close so that the amount of light introduced into the lens is adjusted, which is also called an iris since it functions similar to the iris of the eye.
An iris driving device adjusts the amount of light introduced into the lens by controlling a blade located at the front of the lens to be moved to a specific location by user selection or automated setup. At this time, the blade moving to a specific location should maintain a predetermined location until another control signal is input.
In the existing technique, complicated physical structures using one or more elastic bodies such as a torsion spring, a plurality of engaged gears or the like are applied to maintain the position of the blade moved to a specific location.
However, the conventional structure makes the device complex and large and thus may not be easily mounted to a portable terminal which essentially demands a small and light design. In addition, due to the complex structure, the conventional structure may malfunction frequently. Moreover, since the physically engaged structure may be deviated or damaged just by a small impact, a failure may easily occur.
In addition, in case of a camera module in which functions such as auto focus (AF) or auto image stabilization (OIS) are implemented, an additional physical structure independent from the structure for implementing these functions should be provided, and thus it is considerably difficult to combine this structure harmoniously with the structure for the AF operation or the OIS operation.
Further, in case of a portable terminal in which various functions are combined, it is needed that each function consumes a low power. However, in the conventional structure, the complexly combined or engaged structure should be physically driven as a whole, which is however inefficient in view of power consumption.